I apologize for the mistake. It was the Phalangists militia, not Druze militia.

Here is an account of those events:

On September 1, as the last PLO guerrillas are shipping out of Beirut, President Reagan announces his "Reagan Plan" for solving the Arab-Israeli conflict. It calls for an immediate freeze on Israeli settlement construction in the West Bank and Gaza, advocates Palestinian self rule "in association with Jordan," and explicitly ruled out Israeli annexation of the Palestinian occupied territories. Reagan affirmed UN Resolution 242, emphasizing that it was his understanding that the resolution called for the withdrawal of Israeli forces from the territories (as well as the Sinai, which is as far as the Israelis had been willing to interpret the meaning of the resolution, a demand which Israel believes it has met with the Camp David Treaty).

The plan outraged President Asad because it failed to even mention Syria or its own Israeli occupied Golan Heights. The Israelis, obviously, were also outraged. A shocked Begin called it "the saddest day of my life." The plan was a bungled, half baked attempt to mollify the Arabs based on a State Department draft brief which had never been meant to go public.

The result, however, was that Israel simply deepened efforts to advance its cause in Lebanon, sometimes at American expense through secret negotiations with the Christian Gemayel government, and, by withholding from the US intelligence such as advance warnings of the plan to blow up the US Marine barracks on October 23, 1983.

On September 8, the Arabs issued the "Fez Plan," calling for complete Israeli withdrawal from the occupied territories, including East Jerusalem, and a Palestinian state under the leadership of the PLO in exchange for which Arabs will recognize Israel's right to exist. (Khouri, p. 437)

On September 14, 1982, Lebanese President elect Bashir Gemayal is killed in a bomb explosion just one week before he is due to be sworn in. His brother, Amin, is elected president. The Israeli Defense Forces under the command of Ariel Sharon move into Beirut and occupies the city. On Thursday, September 16, 1982, Lebanese Christian Phalangist troops, with the IDF looking on from surrounding rooftops, enter the Palestinian refugee camps of Sabra and Shatilla in Beirut and begin massacring the residents. The killing will continue until Saturday morning. At least 700 - 800 are killed, with some estimates ranging up to 2,000.